As modern electronics become smaller and are able to produce data at quicker rates, often times the transmission of data becomes constrained by the bandwidth of the communications channel rather than the transmission rates of a device. Therefore, while advances in transmission speeds have the potential to speed up end-to-end communications between devices, often that potential is not realized due to the bandwidth constraints of the communications channel between the devices over which the data is transmitted.
In an attempt to maximize the amount of data that can be sent over a given communications channel at a given time, various methods of modulating and demodulating data have been used to increase the throughput of a channel. For instance various modulation techniques such as binary phase shift keying (BPSK), amplitude shift keying (ASK), or code shift keying (CSK) have been utilized to make efficient use of the bandwidth constraints presented by a given channel.
However, once a communications system is established, it can be a challenge to increase the throughput of a given channel without affecting legacy users of an existing communication channel. For instance, if a new modulation technique is employed by a transmitter of a given communication systems, legacy users of the system may not have the required demodulation hardware needed to work with the new modulation technique and thus these legacy users would not be able to participate in the new system without having to replace their existing hardware.